This invention relates generally to the field of drug screening assays, more particularly to antiviral drug screening assays and specifically to cell fusion based antiviral drug screening assays.
Cell fusion assays designed to identify viral inhibitory agents, i.e., agents that inhibit the binding of a viral glycoprotein and a target cell receptor as well as the virion-cell fusion that follows this binding event, are known in the art. In cell fusion assays, a first cell expresses a viral envelope coat protein on its surface and represents the xe2x80x9cvirionxe2x80x9d while a second cell expresses a receptor for the viral coat protein on its surface and represents the target cell. When brought together under appropriate conditions, the first and second cells fuse via a viral coat protein/target cell receptor mediated event.
Many of the cell fusion assays currently employed are xe2x80x9cvacciniaxe2x80x9d based fusion assays in which the envelope protein of the virion of interest is only transiently expressed in the virion host cell. While such vaccinia based cell fusion assays have been extremely useful, they do suffer from certain disadvantages, including an unsuitability for adaptation to high throughput automated formats.
As such, there is continued interest in the identification of additional cell fusion assay protocols. Of particular interest would be the development of protocol that are adaptable to high throughput, automated formats.
Relevant Literature
Papers of interest include: Berger et al., HIV: A Practical Approach (J. Karn ed. IRL Press) Vol. 2:123-145 (1995); Blondell et al., Abstract from 3rd Annual Conference on AIDS research in California, Feb. 25, 2000; Weiss et al., J. Virol. (1993) 67: 7060-7066; and Weiss et al., AIDS (1996) 10:241-246.
Cell fusion assays for identifying antiviral compounds, particularly enveloped virus inhibitory compounds, are provided. In the cell fusion assays of the subject invention, a first cell that stably expresses an envelope protein of an enveloped virion on its surface, i.e., the xe2x80x9cvirion cell,xe2x80x9d and a second cell that stably expresses a receptor for the envelope protein on its surface, i.e., the xe2x80x9ctarget cell,xe2x80x9d are employed. The virion and target cells each contain one component of a two component reporter system, e.g., a Tat based two component reporter system, that produces a detectable signal in the presence of cell fusion. In practicing the subject screening methods, the first and second cells are contacted with each other under cell fusion conditions in the presence of a candidate inhibitory agent. Next, the presence or absence of the detectable signal is detected. Finally, the inhibitory activity of the candidate agent is derived from the presence or absence of the detectable signal. Also provided are high throughput embodiments of the subject methods. In addition to the subject methods, systems and kits for performing the subject methods are provided.